Re: Using rules from Solve
- To: mathgroup at smc.vnet.net
- Subject: [mg33697] Re: Using rules from Solve
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Tue, 9 Apr 2002 01:01:59 -0400 (EDT)
- Organization: Universitaet Leipzig
- References: <a8m2vj$oag$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
- Sender: owner-wri-mathgroup at wolfram.com
Hi, can you make postings without obvious syntax errors ? and do you mean ReplaceAll[] instead of Replace[] ? Regards Jens postman wrote: > > Hey All: > I appreciate any help with the following. I have a working solution, > but don't understand why my first attempt failed. I'm using Solve to > generate solutions to a set of simultaneous equations (the mass action > equations in chemistry), then want to use the resulting solutions to > calculate numerical values for specific values of the parameters. > > KdEqn={Kd==R*L/RL, RT=RL+R} > > Solve[KdEqn,RL,{RF}] gives me a rule, > > {{RL->L*RT/(Kd+L)}} > > and Replace[RL,Flatten[Solve[KdEqn,RL,{RF}]]] gives an expression > > L*RT/(Kd+L) > > that looks like what I would type on the right hand side of a > function: > > Rl[L_] := L*RT/(Kd+L) > > The problem is that > > Rl[L_] := Replace[RL,Flatten[Solve[KdEqn,RP]{Rf}]] > > fails; Rl[1] does not substitute the value "1" for "L". However, > > Rl[L_] = Replace[RL,Flatten[Solve[KdEqn,RP]{Rf}]] > > works as I want. Why does the := construct fail here? > > Thanks for any help!